[ramidus]

get a piece of polyurathane or polystyrene foam board/rolls. Cut to fit top of closet against ceiling. Wrap foam in 2-3 sheets of newspaper. trim, tape and seal package as tight as possible. Trim and Wrap package w/ spaceblanket. Wrap package again w/ newspaper, again with spaceblanket. Ta-Da! Place on ceiling or walls of closet. Cover w/ reflective mylar if u have any. TA-DA! You just made R-30 or better insulation.

Do not allow it to come into direct contact with any heat source like a lamp or heater. Avoid placing holes in package. Avoid running electrical wiring through package if possible. Significant heat can and will melt materials used in construction of package.